Instant messaging (IM) applications have become increasingly popular as they allow users to exchange text messages using conventional mobile and stationary computing devices, such as PDAs, cell phones, laptop and desktop computers and the like. Typically, an application running on the computing device allows the user to access a list of contacts to quickly initiate a messaging session with a selected friend, co-worker or other user. Each contact is associated with an identifier that allows the messaging infrastructure to route messages to the designated user. Additionally, the messaging application provides presence information to allow the user to determine which of the contacts are currently on-line.
IM allows a user to send and receive messages nearly instantaneously with other IM service users over a network or collection of networks, such as the Internet. IM services are provided by service providers such as “MICROSOFT” Corporation. A computer connected to the Internet can access the IM service using a client application. The client application can be implemented as a local client or a browser based client. A local client is a program which is stored on the computer and provides an interface allowing a user to access the IM service. A browser based client is a program which is generally provided by a web server. The interface loaded from the server allows the user to access the IM service. IM services are provided to an IM service domain, which is comprised of entities having an account with the IM service.
To use IM, a user establishes an account by providing account information including a user identifier, a password, and a list of messenger contacts. Subsequent login to the service requires the user to provide the user identifier and password. Upon confirmation of the login information with the user's account information, the particular client (either local or browser based) displays an interface indicating the user's presence, messenger contact list and the presence of each contact. Presence is a status indication of whether an entity is online or offline. In another embodiment, a presence can have a state of “busy”, “away”, “out to lunch”, or other states. If the entity, such as the user or a contact on the user's messenger contact list, is logged in to a messenger server within the IM service, than the entity's presence is “online”. Otherwise, the presence for the entity is “offline”.
The user may select a contact from the messenger contact list displayed in an IM interface to initiate a conversation. Once selected, the client application associated with each conversation member provides a conversation window. In some IM systems, the client applications associated with a conversation receive direct contact information for each other to provide direct communication between them. In other IM services, the client applications for each conversation member are connected to each other through the IM system. When a conversation member sends a message, the IM system receives the message, finds the recipient member's computer location and routes the message to the particular computer. IM services such as “WINDOWS LIVE MESSENGER” use this method. Instant messaging (IM) services are typically limited to interactions between users of a specific messaging service/network, although some services offer inter-connectivity between services/networks.
Short Message Service (SMS) is a service that enables users to exchange short text messages over a communication network. Text messages can originate from various sources, such as by a mobile device (e.g., mobile phone, PDA, etc.) configured to exchange text messages. SMS is a store and forward service, i.e., text messages are not sent directly from sender to recipient, but always via a Short Message Service Center (SMSC). The SMSC handles and manages the text messages by routing text messages between mobile users via each device's Mobile Station International Subscriber Directory Number (MSISDN).